U.S. patent application number 12/958517 was filed with the patent office on 2012-06-07 for intermediate transfer member reconditioning.
This patent application is currently assigned to XEROX CORPORATION. Invention is credited to Jeremy John Bean, Jonathan H. Herko, Frank Mezzatesta, Dante M. Pietrantoni, Heiko Rommelmann, Yuhua Tong, Jin Wu.
Application Number | 20120141157 12/958517 |
Document ID | / |
Family ID | 46083118 |
Filed Date | 2012-06-07 |
United States Patent
Application |
20120141157 |
Kind Code |
A1 |
Pietrantoni; Dante M. ; et
al. |
June 7, 2012 |
INTERMEDIATE TRANSFER MEMBER RECONDITIONING
Abstract
There is disclosed a method for reconditioning an intermediate
transfer member and the reconditioned intermediate transfer member.
The method comprises stripping off an outer layer of the
intermediate transfer member. A mixture of a polymer, conductive
particles and a solvent is coated over the outer surface of a
seamless intermediate transfer member. The mixture is heated to
form a layer on the outer surface of the intermediate transfer
belt. An apparatus for reconditioning an intermediate transfer
member is also described.
Inventors: |
Pietrantoni; Dante M.;
(Rochester, NY) ; Tong; Yuhua; (Webster, NY)
; Wu; Jin; (Pittsford, NY) ; Mezzatesta;
Frank; (Penfield, NY) ; Bean; Jeremy John;
(Rochester, NY) ; Rommelmann; Heiko; (Penfield,
NY) ; Herko; Jonathan H.; (Walworth, NY) |
Assignee: |
XEROX CORPORATION
Norwalk
CT
|
Family ID: |
46083118 |
Appl. No.: |
12/958517 |
Filed: |
December 2, 2010 |
Current U.S.
Class: |
399/109 |
Current CPC
Class: |
Y10T 29/49746 20150115;
Y10T 29/49726 20150115; Y10T 29/49545 20150115; G03G 15/161
20130101; G03G 15/162 20130101 |
Class at
Publication: |
399/109 |
International
Class: |
G03G 15/00 20060101
G03G015/00 |
Claims
1. A method for reconditioning an intermediate transfer member
comprising: stripping off an outer surface of the intermediate
transfer member with an alcohol; coating a mixture of polymer,
conductive particles and a solvent over the outer surface of a
seamless intermediate transfer member; and heating the mixture to
form a surface layer on the outer surface of the intermediate
transfer belt.
2. The method of claim 1 wherein the alcohol is selected from
methanol, ethanol, 1-propanol, isopropanol, 1-butanol, 2-butanol
and the like and mixtures thereof.
3. The method of claim 1 wherein the solvent is selected from the
group consisting of tetrahydrofuran, alcohols, methyl ethyl ketone,
methyl isobutyl ketone, N,N'-dimethylformamide,
N,N'-dimethylacetamide, N-methylpyrrolidone and methylene
chloride.
4. The method of claim 1 wherein the conductive particles are
selected from the group consisting of carbon black, graphite,
acetylene black, fluorinated carbon black, metal oxides, doped
metal oxides polyaniline, polythiophenes, polyacetylene,
poly(p-phenylene vinylene), poly(p-phenylene sulfide), pyrroles,
polyindole, polypyrene, polycarbazole, polyazulene, polyazepine,
poly(fluorine), polynaphthalene and mixtures thereof.
5. The method of claim 1 wherein the polymer is selected from the
group consisting of fluorinated polymer, polycarbonate, polyester,
polysulfone, polyethersulfone, polyphenylsulfone, polyamide,
polyphenylsulfide, phenoxy resin, polyimide, polyamideimide,
polyetherimide and mixtures thereof.
6. The method of claim 1 wherein the surface layer comprises a
thickness of from about 10 microns to about 150 microns.
7. The method of claim 1 wherein the surface layer comprises a
surface resistivity of from about 10.sup.9 ohms/square to about
10.sup.13 ohms/square.
8. The method of claim 1 wherein the reconditioned intermediate
transfer member comprises a volume resistivity of from about
10.sup.9 ohm-cm to about 10.sup.13 ohm-cm.
9. The method of claim 1 wherein the seamless intermediate transfer
belt comprises a polymer selected from the group consisting of
polyimides, polyamides, polyamideimides, polyetherimides,
polycarbonates, polysulfones, polyethersulfones,
polyphenylsulfones, polyesters, polyphenylsulfides and mixtures
thereof.
10. The method of claim 1 wherein the coating comprises flow
coating.
11. An apparatus for reconditioning an intermediate transfer member
comprising: a drive mechanism for rotating and tensioning an
intermediate transfer belt; a flow coating dispensing member for
applying to the intermediate transfer belt an overcoat solution
wherein the flow coating dispensing member is movable both parallel
and perpendicular to a direction of rotation of the intermediate
transfer belt.
12. The apparatus of claim 11 wherein the drive mechanism comprises
a drive roller.
13. The apparatus of claim 11 wherein the dispensing member is
selected from the group consisting of a slot die and a brush.
14. The apparatus of claim 11 wherein the drive mechanism rotates
the intermediate transfer belt at a rotational speed of from about
10 rpm to about 1500 rpm.
15. The apparatus of claim 11 wherein the flow coating solution
comprises a polymer selected from the group consisting of
fluorinated polymer, polycarbonate, polyester, polysulfone,
polyethersulfone, polyphenylsulfone, polyamide, polyphenylene
sulfide, phenoxy resin, polyimide, polyamideimide and
polyetherimide, conductive particles and a solvent.
16. The apparatus of claim 11 further comprising a doctor blade to
smooth the flow coating solution.
17. A method for reconditioning an intermediate transfer member
comprising: stripping off an outer layer of the intermediate
transfer member with isopropanol; flow coating a mixture of a
polymer, conductive particles and a solvent over an outer surface
of a seamless intermediate transfer member; and heating the mixture
to form a surface layer on the outer surface of the intermediate
transfer belt wherein the surface layer comprises a thickness of
from about 10 microns to about 150 microns and a surface
resistivity of from about 10.sup.9 ohms/square to about 10.sup.13
ohms/square.
18. The method of claim 17 wherein the polymer is selected from the
group consisting of fluorinated polymer, polycarbonate, polyester,
polysulfone, polyethersulfone, polyphenylsulfone, polyamide,
polyphenylsulfide, phenoxy resin, polyimide, polyamideimide,
polyetherimide and mixtures thereof.
19. The method of claim 18 wherein the surface layer comprises from
about 0.1 parts by weight to about 50 parts by weight of conductive
particles.
20. The method of claim 18 wherein the conductive particles
comprise carbon black.
Description
BACKGROUND
[0001] 1. Field of Use
[0002] This disclosure is directed to an image-forming apparatus
and an intermediate transfer member.
[0003] 2. Background
[0004] Image-forming apparatuses in which a color or black and
white image is formed by using an intermediate transfer member to
electrostatically transfer toner are well known. When an image is
formed on a sheet of paper in a color image-forming apparatus using
such an intermediate transfer member, four color images in yellow,
magenta, cyan and black respectively are generally first
transferred sequentially from an image carrier such as a
photoreceptor and superimposed on the intermediate transfer member
(the primary transfer). This full color image is then transferred
to a sheet of paper in a single step (the secondary transfer). In a
black and white image-forming apparatus, a black image is
transferred from the photoreceptor, superimposed on an intermediate
transfer member, and then transferred to a sheet of paper.
[0005] Certain intermediate transfer members are in the form of
seamless belts. These intermediate transfer belts (ITBs) are costly
to manufacture; however, seamless belts are advantageous in that
such belts reduce print cycle time. The high cost of these belts is
especially true with large pitch belts, where more expensive
polyimide type polymers are required. It would be desirable to be
able to remanufacture seamless ITBs so that useful life of the
seamless ITBs can be extended. Such remanufacturing requires the
properties of the seamless ITB to meet the requirements of a new
seamless ITB.
SUMMARY
[0006] According to various embodiments there is described a method
for reconditioning an intermediate transfer member. The outer layer
of the intermediate transfer member is stripped with an alcohol. A
mixture of a polymer, conductive particles and a solvent is coated
over the outer surface of a seamless intermediate transfer member.
The mixture is heated to form a layer on the outer surface of the
intermediate transfer belt.
[0007] According to various embodiments, there is disclosed an
apparatus for reconditioning an intermediate transfer belt. The
apparatus includes a drive mechanism for rotating and tensioning an
intermediate transfer belt. A flow coating dispensing member for
applying to the intermediate transfer belt an overcoat solution is
positioned flow coating dispensing member is movable both parallel
and perpendicular to a direction of rotation of the intermediate
transfer belt.
[0008] According to various embodiments there is disclosed a method
for reconditioning an intermediate transfer member. The outer
surface of the intermediate transfer member is stripped or its
outer layer with an alcohol. A mixture of polyvinylidene fluoride,
conductive particles and a solvent is coated over the outer surface
of a seamless intermediate transfer member. The mixture is heated
to form a surface layer on the outer surface of the intermediate
transfer belt wherein the surface layer comprises a thickness of
from about 10 microns to about 150 microns and a surface
resistivity of from about 10.sup.9 ohms/square to about 10.sup.13
ohms/square.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The accompanying drawings, which are incorporated in and
constitute a part of this specification, illustrate several
embodiments of the present teachings and together with the
description, serve to explain the principles of the present
teachings.
[0010] FIG. 1 is a schematic illustration of an image
apparatus.
[0011] FIG. 2 is a schematic representation of an embodiment
disclosed herein.
[0012] FIG. 3 is a schematic representation of an apparatus
suitable for reconditioning a seamless intermediate transfer
member.
[0013] It should be noted that some details of the figures have
been simplified and are drawn to facilitate understanding of the
embodiments rather than to maintain strict structural accuracy,
detail, and scale.
DESCRIPTION OF THE EMBODIMENTS
[0014] Reference will now be made in detail to embodiments of the
present teachings, examples of which are illustrated in the
accompanying drawings. Wherever possible, the same reference
numbers will be used throughout the drawings to refer to the same
or like parts.
[0015] In the following description, reference is made to the
accompanying drawings that form a part thereof, and in which is
shown by way of illustration specific exemplary embodiments in
which the present teachings may be practiced. These embodiments are
described in sufficient detail to enable those skilled in the art
to practice the present teachings and it is to be understood that
other embodiments may be utilized and that changes may be made
without departing from the scope of the present teachings. The
following description is, therefore, merely exemplary.
[0016] Referring to FIG. 1, an image-forming apparatus includes an
intermediate transfer member as described in more detail below. The
image-forming apparatus is an image-forming apparatus of an
intermediate transfer system comprising a first transfer unit for
transferring the toner image formed on the image carrier onto the
intermediate transfer member by primary transfer, and a second
transfer unit for transferring the toner image transferred on the
intermediate transfer member onto the transfer material by
secondary transfer. Also in the image-forming apparatus, the
intermediate transfer member may be provided as a
transfer-conveying member for conveying the transfer material in
the transfer region for transferring the toner image onto the
transfer material. Having the intermediate transfer member that
transfers images of high quality and that remains stable for a long
period is required.
[0017] The image-forming apparatus described herein is not
particularly limited as far as it is an image-forming apparatus of
intermediate transfer type, and examples include an ordinary
monochromatic image-forming apparatus accommodating only a
monochromatic color in the developing device, a color image-forming
apparatus for repeating primary transfer of the toner image carried
on the image carrier sequentially on the intermediate transfer
member, and a tandem color image-forming apparatus having plural
image carriers with developing units of each color disposed in
series on the intermediate transfer member. More specifically, it
may arbitrarily comprise an image carrier, a charging unit for
uniformly charging the surface of the image carrier, an exposure
unit for exposing the surface of the intermediate transfer member
and forming an electrostatic latent image, a developing unit for
developing the latent image formed on the surface of the image
carrier by using a developing solution and forming a toner image, a
fixing unit for fixing the toner unit on the transfer material, a
cleaning unit for removing toner and foreign matter sticking to the
image carrier, a destaticizing unit for removing the electrostatic
latent image left over on the surface of the image carrier, and
others by known methods as required.
[0018] As the image carrier, a known one may be used. As its
photosensitive layer, an organic system, amorphous silicon, or
other known material may be used. In the case of the image carrier
of cylindrical type, it is obtained by a known method of molding
aluminum or aluminum alloy by extrusion, and processing the
surface. A belt form image carrier may also be used.
[0019] The charging unit is not particularly limited, and known
chargers may be used, such as a contact type charger using a
conductive or semiconductive roller, brush, film and rubber blade,
scorotron charger or corotron charge making use of corona
discharge, and others. Above all, the contact type charging unit
has excellent charge compensation capability. The charging unit
usually applies DC current to the electrophotographic
photosensitive material, but AC current may be further
superposed.
[0020] The exposure unit is not particularly limited, and, for
example, an optical system device may be used, which exposes a
desired image on the surface of the electrophotographic
photosensitive material by using a light source such as a
semiconductor laser beam, LED beam, liquid crystal shutter beam or
the like, or through a polygonal mirror from such light source.
[0021] The developing unit may be properly selected depending on
the purpose, and, for example, a known developing unit for
developing by using one-pack type developing solution or two-pack
type developing solution, with or without contact, using brush and
roller may be used.
[0022] The first transfer unit includes known transfer chargers
such as a contact type transfer charger using a member, roller,
film and rubber blade, and scorotron transfer charger or corotron
transfer charger making use of corona discharge. Above all, the
contact type transfer charger provides excellent transfer charge
compensation capability. Aside from the transfer charger, a peeling
type charger may be also used together.
[0023] The second transfer unit may be same as the first transfer
unit such as a contact type transfer charger using a transfer
roller and others, scorotron transfer charger and corotron transfer
charger. By pressing firmly by the transfer roller of the contact
type transfer charger, the image transfer stage can be maintained.
Further, by pressing the transfer roller or the contact type
transfer charger at the position of the roller for guiding the
intermediate transfer member, the action of moving the toner image
from the intermediate transfer member to the transfer material may
be done.
[0024] As the photo destaticizing unit, for example, a tungsten
lamp or LED may be used, and the light quality used in the photo
destaticizing process may include white light of tungsten lamp and
red light of LED. As the irradiation light intensity in the photo
destaticizing process, usually the output is set to be about
several times to 30 times of the quantity of light showing the half
exposure sensitivity of the electrophotographic photosensitive
material.
[0025] The fixing unit is not particularly limited, and any known
fixing unit may be used, such as a heat roller fixing unit and an
oven fixing unit.
[0026] The cleaning unit is not particularly limited, and any known
cleaning device may be used.
[0027] A color image-forming apparatus for repeating primary
transfer is shown schematically in FIG. 1. The image-forming
apparatus shown in FIG. 1 includes a photosensitive drum 1 as an
image carrier, a transfer member 2 as an intermediate transfer
member such as a transfer belt, a bias roller 3 as a transfer
electrode, a tray 4 for feeding paper as transfer material, a
developing device 5 by BK (black) toner, a developing device 6 by Y
(yellow) toner, a developing device 7 by M (magenta) toner, a
developing device 8 by C (cyan) toner, a member cleaner 9, a
peeling pawl 13, rollers 21, 23 and 24, a backup roller 22, a
conductive roller 25, an electrode roller 26, a cleaning blade 31,
a block of paper 41, a pickup roller 42, and a feed roller 43.
[0028] In the image-forming apparatus shown in FIG. 1, the
photosensitive drum 1 rotates in the direction of arrow A, and the
surface of the charging device (not shown) is uniformly charged. On
the charged photosensitive drum 1, an electrostatic latent image of
a first color (for example, BK) is formed by an image writing
device such as a laser writing device. This electrostatic latent
image is developed by toner by the developing device 5, and a
visible toner image T is formed. The toner image T is brought to
the primary transfer unit comprising the conductive roller 25 by
rotation of the photosensitive drum 1, and an electric field of
reverse polarity is applied to the toner image T from the
conductive roller 25. The toner image T is electrostatically
adsorbed on the transfer member 2, and the primary transfer is
executed by rotation of the transfer member 2 in the direction of
arrow B.
[0029] Similarly, a toner image of a second color, a toner image of
a third color and a toner image of a fourth color are sequentially
formed, and overlaid on the transfer member 2, and a multi-layer
toner image is formed.
[0030] The multi-layer toner image transferred on the transfer
member 2 is brought to the secondary transfer unit comprising the
bias roller 3 by rotation of the transfer member 2. The secondary
transfer unit comprises the bias roller 3 disposed at the surface
side carrying the toner image of the transfer member 2, backup
roller 22 disposed to face the bias roller 3 from the back side of
the transfer member 2, and electrode roller 26 rotating in tight
contact with backup roller 22.
[0031] The paper 41 is taken out one by one from the paper block
accommodated in the paper tray 4 by means of the pickup roller 42,
and is fed into the space between the transfer member 2 and bias
roller 3 of the secondary transfer unit by means of the feed roller
43 at a specified timing. The fed paper 41 is conveyed under
pressure between the bias roller 3 and backup roller 22, and the
toner image carried on the transfer member 2 is transferred thereon
by rotation of the transfer member 2.
[0032] The paper 41 on which the toner image is transferred, is
peeled off from the transfer member 2 by operating the peeling pawl
13 at the retreat position until the end of primary transfer of the
final toner image, and conveyed to the fixing device (not shown).
The toner image is fixed by pressing and heating, and a permanent
image is formed. After transfer of the multi-layer toner image onto
the paper 41, the transfer member 2 is cleaned by the cleaner 9
disposed at the downstream side of the secondary transfer unit to
remove the residual toner, and is ready for next transfer. The bias
roller 3 is provided so that the cleaning blade 31 made of
polyurethane or the like may be always in contact, and toner
particles, paper dust and other foreign matter sticking by transfer
are removed.
[0033] In the case of transfer of a monochromatic image, the toner
image T after primary transfer is immediately sent to the secondary
transfer process, and is conveyed to the fixing device, but in the
case of transfer of a multi-color image by combination of plural
colors, the rotation of the transfer member 2 and photosensitive
drum 1 is synchronized so that the toner images of plural colors
may coincide exactly in the primary transfer unit, and deviation of
toner images of colors is prevented. In the secondary transfer
unit, by applying a voltage of the same polarity (transfer voltage)
as the polarity of the toner to the electrode roller 26 tightly
contacting with the backup roller 22 disposed oppositely through
the bias roller 3 and transfer member 2, the toner image is
transferred onto the paper 41 by electrostatic repulsion. Thus, the
image is formed.
[0034] The intermediate transfer member 2 can be of any suitable
configuration. Examples of suitable configurations include a sheet,
a film, a web, a foil, a strip, a coil, a cylinder, a drum, an
endless mobius strip, a circular disc, a belt including an endless
belt, an endless seamed flexible belt, an endless seamless flexible
belt, an endless belt having a puzzle cut seam, and the like. In
FIG. 1, the transfer member 2 is depicted as a belt.
[0035] In an image on image transfer, the color toner images are
first deposited on the photoreceptor and all the color toner images
are then transferred simultaneously to the intermediate transfer
member. In a tandem transfer, the toner image is transferred one
color at a time from the photoreceptor to the same area of the
intermediate transfer member. Both embodiments are included
herein.
[0036] Transfer of the developed image from the photoconductive
member to the intermediate transfer member and transfer of the
image from the intermediate transfer member to the paper can be by
any suitable technique conventionally used in electrophotography,
such as corona transfer, pressure transfer, bias transfer, and
combinations of those transfer means, and the like.
[0037] The intermediate transfer member 2 can be of any suitable
configuration. Examples of suitable configurations include a sheet,
a film, a web, a foil, a strip, a coil, a cylinder, a drum, an
endless strip, a circular disc, a drelt (a cross between a drum and
a belt), a belt including an endless belt, an endless seamed
flexible belt, and an endless seamed flexible imaging belt.
[0038] A belt is one embodiment of intermediate transfer member.
Certain intermediate transfer members are in the form of seamless
belts. These intermediate transfer belts (ITBs) are costly to
manufacture. Disclosed is a method to recondition or remanufacture
seamless ITBs. The reconditioned or remanufactured belt is also
described.
[0039] The method comprises obtaining a seamless intermediate
transfer belt that no longer produces print of an acceptable
quality. An outer layer of the intermediate transfer belt is
stripped off with an alcohol. The alcohol is selected from
methanol, ethanol, 1-propanol, isopropanol, 1-butanol, 2-butanol
and the like and mixtures thereof. A mixture of a polymer such as
fluorinated polymer, polycarbonate, polyester, polysulfone,
polyethersulfone, polyphenylsulfone, polyamide, polyphenylene
sulfide, phenoxy resin, polyimide, polyamideimide, or
polyetherimide, conductive particles and a solvent is coated over
an outer surface of the seamless intermediate transfer member. The
mixture is heated to form a layer on the outer surface of the
intermediate transfer belt.
[0040] For the acceptable toner transfer, both onto and off a
remanufactured ITB, the final image produced across the
remanufactured ITB must be comparable in quality to images formed
across the original belt. Transfer fields are very sensitive to the
resistivity and thickness of the materials used to overcoat the
belt. To successfully function, the electrical properties of the
remanufactured ITB should be carefully controlled. Overcoat
thickness, uniformity, resistivity and adhesion are some of the key
parameters to be controlled.
[0041] Suitable polyimides for the overcoat layer include those
formed from various diamines and dianhydrides, polyamideimide, and
polyetherimide. For example, polyimides that include aromatic
polyimides such as those formed by the reacting pyromellitic acid
and diaminodiphenylether are sold under the tradename
KAPTON.RTM.-type-HN, available from DuPont. Another suitable
polyimide available from DuPont and sold as KAPTON.RTM.-Type-FPC-E,
is produced by imidization of copolymeric acids such as
biphenyltetracarboxylic acid and pyromellitic acid with two
aromatic diamines such as p-phenylenediamine and
diaminodiphenylether. Another suitable polyimide includes
pyromellitic dianhydride and benzophenone tetracarboxylic
dianhydride copolymeric acids reacted with
2,2-bis[4-(8-aminophenoxy)phenoxy]-hexafluoropropane available as
EYMYD type L-20N from Ethyl Corporation, Baton Rouge, La. Other
suitable aromatic polyimides include those containing
1,2,1',2'-biphenyltetracarboximide and para-phenylene groups such
as UPILEX.RTM.-S available from Uniglobe Kisco, Inc., White Planes,
N.Y., and those having biphenyltetracarboximide functionality with
diphenylether end spacer characterizations such as UPILEX.RTM.-R
also available from Uniglobe Kisco, Inc. Mixtures of polyimides can
also be used. More commercial polyimide examples that can be used
as the substrate layer 50 include PYRE M.L.RTM. RC-5019, RC 5057,
RC-5069, RC-5097, RC-5053, and RK-692, all commercially available
from Industrial Summit Technology Corporation, Parlin, N.J.; RP-46
and RP-50, both commercially available from Unitech LLC, Hampton,
Va.; DURIMIDE.RTM. 100, commercially available from FUJIFILM
Electronic Materials U.S.A., Inc., North Kingstown, R.I.
[0042] Other Examples of polyimides include in the overcoat layer
are KAPTON.RTM. KJ, commercially available from E.I. DuPont,
Wilmington, Del., as represented by
##STR00001##
wherein x is equal to 2; y is equal to 2; m and n are the same or
different and are from about 10 to about 300; IMIDEX.RTM.,
commercially available from West Lake Plastic Company, as
represented by
##STR00002##
wherein z is equal to 1, and q is from about 10 to about 300; and
EXTEM.RTM. XH-1005, commercially available from Sabic Innovative
Plastics, as represented by
##STR00003##
wherein n is from about 10 to about 1,000.
[0043] Examples of polyamideimides that can be utilized as overcoat
layers are VYLOMAX.RTM. HR-11NN (15 weight percent solution in
N-methylpyrrolidone, T.sub.g=300.degree. C., and M.sub.w=45,000),
HR-12N2 (30 weight percent solution in
N-methylpyrrolidone/xylene/methyl ethyl ketone=50/35/15,
T.sub.g=255.degree. C., and M.sub.w=8,000), HR-13NX (30 weight
percent solution in N-methylpyrrolidone/xylene=67/33,
T.sub.g=280.degree. C., and M.sub.w=10,000), HR-15ET (25 weight
percent solution in ethanol/toluene=50/50, T.sub.g=260.degree. C.,
and M.sub.w=10,000), HR-16NN (14 weight percent solution in
N-methylpyrrolidone, T.sub.g=320.degree. C., and M.sub.w=100,000),
all commercially available from Toyobo Company of Japan, and
TORLON.RTM. AI-10 (T.sub.g=272.degree. C.), commercially available
from Solvay Advanced Polymers, LLC, Alpharetta, Ga.
[0044] Examples of polyetherimide overcoat layers are ULTEM.RTM.
1000 (T.sub.g=210.degree. C.), 1010 (T.sub.g=217.degree. C.), 1100
(T.sub.g=217.degree. C.), 1285, 2100 (T.sub.g=217.degree. C.), 2200
(T.sub.g=217.degree. C.), 2210 (T.sub.g=217.degree. C.), 2212
(T.sub.g=217.degree. C.), 2300 (T.sub.g=217.degree. C.), 2310
(T.sub.g=217.degree. C.), 2312 (T.sub.g=217.degree. C.), 2313
(T.sub.g=217.degree. C.), 2400 (T.sub.g=217.degree. C.), 2410
(T.sub.g=217.degree. C.), 3451 (T.sub.g=217.degree. C.), 3452
(T.sub.g=217.degree. C.), 4000 (T.sub.g=217.degree. C.), 4001
(T.sub.g=217.degree. C.), 4002 (T.sub.g=217.degree. C.), 4211
(T.sub.g=217.degree. C.), 8015, 9011 (T.sub.g=217.degree. C.),
9075, and 9076, all commercially available from Sabic Innovative
Plastics.
[0045] Examples of polyamide polymers as the overcoat layer include
aliphatic polyamides such as Nylon 6 and Nylon 66 from DuPont; semi
aromatic polyamides, or polyphthalamides such as TROGAMID.RTM. 6T
from Evonik Industries; and aromatic polyamides, or aramides such
as KEVLAR.RTM. and NOMEX.RTM. from DuPont, and TEIJINCONEX.RTM.,
TWARON.RTM. and TECHNORA.RTM. from Teijin.
[0046] Examples of phenoxy resin overcoat layers are represented
by
##STR00004##
wherein m is from about 40 to about 400 or from about 70 to about
350 or from about 100 to about 400. The phenoxy resin is formed
from reacting a diphenol with epichlorohydrin. In embodiments,
polymers of bisphenol A and epichlorohydrin are included. Other
polymers of diphenol and epichlorohydrin can also be included such
as polymers of bisphenol Z and epichlorohydrin, polymers of
bisphenol AF and epichlorohydrin, polymers of bisphenol C and
epichlorohydrin, polymers of bisphenol S and epichlorohydrin, and
polymers of bisphenol BP and epichlorohydrin. Commercial phenoxy
resins are available from InChem Corp., Rock Hill, S.C. including
PKFE (M.sub.n=16,000 and M.sub.w=60,000), PKHB (M.sub.n=9,500 and
M.sub.w=32,000), PKHC (M.sub.n=11,000 and M.sub.w=43,000), PKHH
(M.sub.n=13,000 and M.sub.w=52,000), PKHJ (M.sub.n=16,000 and
M.sub.w=57,000), and PKHP (M.sub.n=13,000 and M.sub.w=52,000).
[0047] Examples of polyester polymers as the overcoat layer include
aliphatic polyesters such as polyglycolic acid, polylactic acid and
polycaprolactone; aliphatic copolyesters such as polyethylene
adipate and polyhydroxyalkanoate; semi aromatic copolyesters such
as polyethylene terephthalate (PET), polybutylene terephthalate
(PBT), polytrimethylene terephthalate (PTT), and polyethylene
naphthalate (PEN); aromatic copolyesters such as VECTRAN.RTM..
[0048] Polysulfones, polyphenylsulfones and polyethersulfones
selected for the overcoat layer disclosed herein are represented in
embodiments for by for example
##STR00005##
where n represents the number of repeating units, and more
specifically where n is for example, a number of from about 30 to
about 5,000, from about 80 to about 3,500, from about 150 to about
3,000, and yet more specifically from about 200 to about 2,000.
Commercially obtainable polysulfone examples include UDEL.RTM.
P-1700, P-3500; commercially obtainable polyphenylsulfone examples
include RADEL.RTM. 5000NT, 5100NT15, 5900NT; commercially
obtainable polyethersulfone examples include RADEL.RTM. A-200A,
AG-210NT, AG-320NT, VERADEL.RTM. 3000P, 3100P, 3200P, all available
or obtainable from Solvay Advanced Polymers, LLC, Alpharetta, Ga.
In an embodiment the number average molecular weight of each of the
polysulfone, the polyphenylsulfone and the polyethersulfone is for
example, from about 2,000 to about 50,000, or from about 4,000 to
about 20,000, and the weight average molecular weight of the
polysulfones, the polyphenylsulfones and the polyethersulfones are
for example from about 10,000 to about 200,000, or from about
50,000 to about 150,000.
[0049] Examples of polyphenylene sulfide polymers as the overcoat
layer include RYTON.RTM. polyphenylene sulfide by Chevron Phillips
as cross-linked type of polymer, FORTRON.RTM. polyphenylene sulfide
by Ticona as a linear polymer; and SULFAR.RTM. polyphenylene
sulfide by Testori.
[0050] Examples of polycarbonate polymers as the overcoat layer
that are selected include
poly(4,4'-isopropylidene-diphenylene)carbonate (also referred to as
bisphenol-A-polycarbonate), poly(4,4'-cyclohexylidine
diphenylene)carbonate (also referred to as
bisphenol-Z-polycarbonate),
poly(4,4'-isopropylidene-3,3'-dimethyl-diphenyl)carbonate (also
referred to as bisphenol-C-polycarbonate), and the like. In
embodiments, the thermoplastic polymers are comprised of
bisphenol-A-polycarbonate resins, commercially available as
MAKROLON.RTM., with a weight average molecular weight of from about
50,000 to about 500,000.
[0051] Suitable fluorinated polymer overcoat layers include
polyvinylidene fluoride (PVDF), and commercial examples of PVDF are
under the trade names of KYNAR.RTM., HYLAR.RTM., SOLEF.RTM., or
SYGEF.RTM.. KYNAR.RTM. PVDF examples include KYNAR.RTM. 500, 370,
460, 201, 301-F, 711, or 721, and KYNAR FLEX.RTM. PVDF examples
include KYNAR FLEX .RTM. 2500, 2850 or 3120, all available from
Arkema Inc., Philadelphia, Pa.
[0052] Other fluorinated polymers that can be used as overcoat
layers include TEFLON.RTM.-like materials including fluorinated
ethylene propylene copolymer (FEP), polytetrafluoroethylene (PTFE),
polyfluoroalkoxy polytetrafluoroethylene (PFA TEFLON .RTM.) and
other TEFLON.RTM.-like materials; and fluoroelastomers, such as
those sold as VITON.RTM., such as copolymers and terpolymers of
vinylidenefluoride, hexafluoropropylene, and tetrafluoroethylene,
which are known commercially under various designations as VITON
A.RTM., VITON E.RTM., VITON E60C.RTM., VITON E45.RTM., VITON
E430.RTM. VITON B910.RTM. VITON GH.RTM., VITON B50.RTM. VITON E45
and VITON GF.RTM.. The VITON.RTM. designation is a Trademark of
E.I. DuPont de Nemours, Inc. Two known fluoroelastomers are
comprised of (1) a class of copolymers of vinylidenefluoride,
hexafluoropropylene, and tetrafluoroethylene, known commercially as
VITON A.RTM.; (2) a class of terpolymers of vinylidenefluoride,
hexafluoropropylene, and tetrafluoroethylene, known commercially as
VITON B.RTM.; and (3) a class of tetrapolymers of
vinylidenefluoride, hexafluoropropylene, tetrafluoroethylene, and a
cure site monomer, such as VITON GF.RTM., having 35 mole percent of
vinylidenefluoride, 34 mole percent of hexafluoropropylene, and 29
mole percent of tetrafluoroethylene with 2 percent cure site
monomer. The cure site monomer can be those available from E.I.
DuPont de Nemours, Inc. such as
4-bromoperfluorobutene-1,1,1-dihydro-4-bromoperfluorobutene-1,3-b-
romoperfluoropropene-1,1,1-dihydro-3-bromoperfluoropropene-1, or
any other suitable, known, commercially available cure site
monomers.
[0053] Flow coating requires the coating to be applied to a
rotating substrate and applying the coating from an applicator to
the substrate in a controlled amount so that substantially all the
coating that exits the applicator adheres to the substrate.
Specifically, only materials that can be completely dissolved in a
solvent can be flow coated. Further, it is desirable that the
material have the ability to stay dissolved during the entire flow
coating process. Good results are not obtained with materials which
tend to coagulate or crystallize within the time period required
for flow coating.
[0054] An overcoat composition comprising a polymer such as
fluorinated polymer such as PVDF, polycarbonate, polyester,
polysulfone, polyethersulfone, polyphenylsulfone, polyamide,
polyphenylene sulfide, phenoxy resin, polyimide, polyamideimide, or
polyetherimide, conductive particles and a solvent is flow coated
on a seamless intermediate transfer belt that no longer produces
acceptable prints. PVDF is a specialty plastic material in the
fluoropolymer family, generally used in applications requiring high
purity, strength, and resistance to solvents, acids, bases and
heat. The coating is dried and the remanufactured seamless ITB is
suitable for use.
[0055] In an embodiment of a remanufactured intermediate transfer
belt 54 shown in FIG. 2, the intermediate transfer belt 54 is
seamless belt comprised of a polymer 52 and conductive particles
51. The initial belt no longer meets operating specifications. The
seamless ITB has been remanufactured to include a surface layer 56
to restore the belt so that it operates within desired
specifications. The surface layer includes a polymer 58 and
conductive particles 57. The surface layer 56 provides electrical
properties that are within the specification of the original
seamless ITB. FIG. 2 is not to scale. The surface layer 56 has a
thickness of from about 10 microns to about 150 microns, or from
about 15 micron to about 120 microns, or from about 20 micron to
about 100 microns.
[0056] Examples of conductive particles 57 used in the coating and
surface layer 56 of remanufactured seamless ITBs include carbon
blacks such as carbon black, graphite, acetylene black, fluorinated
carbon black, and the like; metal oxides and doped metal oxides,
such as tin oxide, antimony dioxide, antimony-doped tin oxide,
titanium dioxide, indium oxide, zinc oxide, indium oxide,
indium-doped tin trioxide, and polymers such as polyaniline and
polythiophene, and mixtures thereof. The conductive particles 57
may be present in an amount of from about 0.1 parts by weight to
about 50 parts by weight and or from about 3 parts by weight to
about 40 parts by weight, or from about 5 parts by weight to about
20 parts by weight of the total solids of the surface layer 56. The
surface resistivity of the remanufactured or reconditioned ITB is
from about 10.sup.9 ohms/square to about 10.sup.13 ohms/square, or
from about 10.sup.10 ohms/square to about 10.sup.12 ohms/square.
The volume resistivity of the remanufactured or reconditioned ITB
is from about 10.sup.8 ohm-cm to about 10.sup.12 ohm-cm, or from
about 10.sup.9 ohm-cm to about 10.sup.11 ohm-cm. Both the volume
and surface resistivity can be provided by varying the
concentration of the conductive particles 57 in the surface layer
56 to match the initial values of the ITB.
[0057] Examples of carbon blacks selected as the conductive
component for the coating and surface layer 56 include VULCAN.RTM.
carbon blacks, REGAL.RTM. carbon blacks, MONARCH.RTM. carbon blacks
and BLACK PEARLS.RTM. carbon blacks available from Cabot
Corporation. Specific examples of conductive carbon blacks are
BLACK PEARLS.RTM. 1000 (B.E.T. surface area=343 m.sup.2/g, DBP
absorption=1.05 ml/g), BLACK PEARLS.RTM. 880 (B.E.T. surface
area=240 m.sup.2/g, DBP absorption=1.06 ml/g), BLACK PEARLS.RTM.
800 (B.E.T. surface area=230 m.sup.2/g, DBP absorption=0.68 ml/g),
BLACK PEARLS.RTM. L (B.E.T. surface area=138 m.sup.2/g, DBP
absorption=0.61 ml/g), BLACK PEARLS.RTM. 570 (B.E.T. surface
area=110 m.sup.2/g, DBP absorption=1.14 ml/g), BLACK PEARLS.RTM.
170 (B.E.T. surface area=35 m.sup.2/g, DBP absorption=1.22 ml/g),
VULCAN.RTM. XC72 (B.E.T. surface area=254 m.sup.2/g, DBP
absorption=1.76 ml/g), VULCAN.RTM. XC72R (fluffy form of
VULCAN.RTM. XC72), VULCAN.RTM. XC605, VULCAN.RTM. XC305, REGAL.RTM.
660 (B.E.T. surface area=112 m.sup.2/g, DBP absorption=0.59 ml/g),
REGAL.RTM. 400 (B.E.T. surface area=96 m.sup.2/g, DBP
absorption=0.69 ml/g), REGAL.RTM. 330 (B.E.T. surface area=94
m.sup.2/g, DBP absorption=0.71 ml/g), MONARCH.RTM. 880 (B.E.T.
surface area=220 m.sup.2/g, DBP absorption=1.05 ml/g, primary
particle diameter=16 nanometers), and MONARCH.RTM. 1000 (B.E.T.
surface area=343 m.sup.2/g, DBP absorption=1.05 ml/g, primary
particle diameter=16 nanometers); Channel carbon blacks available
from Evonik-Degussa; Special Black 4 (B.E.T. surface area=180
m.sup.2/g, DBP absorption=1.8 ml/g, primary particle diameter=25
nanometers), Special Black 5 (B.E.T. surface area=240 m.sup.2/g,
DBP absorption=1.41 ml/g, primary particle diameter=20 nanometers),
Color Black FW1 (B.E.T. surface area=320 m.sup.2/g, DBP
absorption=2.89 ml/g, primary particle diameter=13 nanometers),
Color Black FW2 (B.E.T. surface area=460 m.sup.2/g, DBP
absorption=4.82 ml/g, primary particle diameter=13 nanometers), and
Color Black FW200 (B.E.T. surface area=460 m.sup.2/g, DBP
absorption=4.6 ml/g, primary particle diameter=13 nanometers).
[0058] Further examples of conductive particles 57 for the coating
and surface layer 56 include doped metal oxides. Doped metal oxides
include antimony doped tin oxide, aluminum doped zinc oxide,
antimony doped titanium dioxide, similar doped metal oxides, and
mixtures thereof.
[0059] Suitable antimony doped tin oxides include those antimony
doped tin oxides coated on an inert core particle (e.g.,
ZELEC.RTM.ECP-S, M and T) and those antimony doped tin oxides
without a core particle (e.g., ZELEC.RTM.ECP-3005-XC and
ZELEC.RTM.ECP-3010-XC, ZELEC.RTM. is a trademark of DuPont
Chemicals Jackson Laboratories, Deepwater, N.J). The core particle
may be mica, TiO.sub.2 or acicular particles having a hollow or a
solid core.
[0060] In another embodiment, the electrically conductive particles
57 for the coating and surface layer 56 include antimony doped tin
oxide coated on an inert core particle (e.g., ZELEC.RTM. ECP-S, M
and T). ZELEC.RTM. is a trademark of DuPont Chemicals Jackson
Laboratories, Deepwater, N.J. The core particle may be mica,
TiO.sub.2 or acicular particles having a hollow or a solid
core.
[0061] In another embodiment, antimony doped tin oxide particles
are prepared by densely layering a thin layer of antimony doped tin
oxide onto the surface of a silica shell or silica-based particle,
wherein the shell, in turn, has been deposited onto a core
particle. The crystallites of the conductor are dispersed in such a
fashion so as to form a dense conductive surface on the silica
layer. This provides optimal conductivity. Also, the particles are
fine enough in size to provide adequate transparency. The silica
may either be a hollow shell or layered on the surface of an inert
core, forming a solid structure. Forms of antimony doped tin oxide
are commercially available under the tradename ZELEC.RTM. ECP
(electroconductive powders) from DuPont Chemicals Jackson
Laboratories, Deepwater, N.J. Specific examples include antimony
doped tin oxides are ZELEC.RTM. ECP 1610-S, ZELEC.RTM. ECP 2610-S,
ZELEC.RTM. ECP 3610-S, ZELEC.RTM. ECP 1703-S, ZELEC.RTM. ECP
2703-S, ZELEC.RTM. ECP 1410-M, ZELEC.RTM. ECP 3005-XC, ZELEC.RTM.
ECP 3010-XC, ZELEC.RTM. ECP 1410-T, ZELEC.RTM. ECP 3410-T,
ZELEC.RTM. ECP-S-X1, and the like. Three commercial grades of
ZELEC.RTM. ECP powders can be used and include an acicular, hollow
shell product (ZELEC.RTM. ECP-S), an equiaxial titanium dioxide
core product (ZELEC ECP-T), and a plate shaped mica core product
(ZELEC.RTM. ECP-M).
[0062] Examples of the solvent used in the coating for the surface
layer 56 include N,N-dimethylformamide, N-methylpyrrolidone,
tetrahydrofuran, alcohols, toluene, hexane, cyclohexane, heptane,
monoclorobenzene, N,N'-dimethylacetamide, methylene chloride,
alcohols and mixtures thereof. The coating of fluorinated polymer
such as PVDF, polycarbonate, polyester, polysulfone,
polyethersulfone, polyphenylsulfone, polyamide, polyphenylene
sulfide, phenoxy resin, polyimide, polyamideimide, or
polyetherimide, conductive particles and solvent, is applied to an
intermediate transfer belt producing prints of unacceptable
quality. The coating is dried to restore the seamless intermediate
transfer belt so that it operates within specification and produces
prints of an acceptable quality.
[0063] Typical techniques for coating the composition on the
intermediate transfer belt include flow coating, liquid spray
coating, dip coating, wire would rod coating, fluidized bed
coating, blade coating and the like. The coating is dried at
temperatures of from about 25.degree. C. to about 370.degree. C.,
or from about 80.degree. C. to about 250.degree. C. for periods of
from about 30 minutes to about 360 minutes, or from about 60
minutes to about 180 minutes to form the surface layer. The heat
can be provided by thermal ovens or IR radiation devices.
[0064] In an embodiment shown in FIG. 3 showing a flow coating
apparatus for reconditioning an intermediate transfer member, the
overcoat composition is pumped from a dispense tank (not shown) to
a dispensing needle 120 (brush, slot die or other dispensing
member). The belt 122 to be remanufactured is held in place and
rotated during the coating operation. The belt 122 can be rotated
by various mechanisms for example, a drive roller, a tensioning
roller and a trailing roller to drive. As the belt 122 is rotated
at a predetermined rotational velocity, the dispensing needle 120
traverses the belt 122 in the direction of arrow A at a
corresponding linear velocity to completely and uniformly coat the
belt. The solvent in the overcoat can be flashed off to completely
dry the coating. A doctor blade 124 smoothes the coating. The
dispensing needle 120 and doctor blade 124 are positioned in
relation to the belt 122 through an X-Y slide mechanism 126. After
the coating is applied it is dried. By this process, it is possible
to remanufacture a belt with a coating that matches the electrical
properties of the ITB. The rotating speed is not critical, but can
be selected from a broad range, such as from about 10 rpm to about
500 rpm, or from about 20 rpm to about 200 rpm, or from about 30
rpm to about 80 rpm.
[0065] Examples of specific seamless intermediate transfer belts
that can be remanufactured include those made of polymers selected
from the group consisting of polyimides, polyamides,
polyamideimides, polyetherimides, polycarbonates, polysulfones,
polyethersulfones, polyphenylsulfones, polyesters, polyphenylene
sulfides and mixtures thereof.
[0066] Specific embodiments will now be described in detail. These
examples are intended to be illustrative, and not limited to the
materials, conditions, or process parameters set forth in these
embodiments. All parts are percentages by solid weight unless
otherwise indicated.
EXAMPLES
[0067] A seamless polyimide ITB which produced prints of
unacceptable quality was obtained. The seamless polyimide ITB had
been in use in an electrophographic machine. The ITB was then
cleaned with isopropanol to remove any toner residues on the
surface, and then air dried. The seamless polyimide ITB was coated,
via a draw bar coater, with an overcoat composed of polyvinylidene
fluoride (PVDF) with carbon black. PVDF is a specialty plastic
material in the fluoropolymer family, generally used in
applications requiring high purity, strength, and resistance to
solvents, acids, bases and heat. Compared to other fluoropolymers,
it has a relatively low cost.
[0068] The details of the overcoat include forming a dispersion of
0.4 grams of an 18.7 weight percent carbon black (Special Black 4)
in N-methylpyrrolidone (NMP). The dispersion was mixed with 1.5
grams of KYNAR.RTM. 301F PVDF resin in 13.5 grams of
N,N'-dimethylformamide (DMF). The mixture was coated on the
seamless polyimide having unacceptable print quality belt by a
2.0-mil Bird bar. The coating was dried at room temperature for 1
hour, and dried at 120.degree. C. for one hour.
[0069] The standard peel test showed strong adhesion between the
polyimide bottom layer and the PVDF surface layer (did not
peel).
[0070] The surface resistivity was about 10.sup.10.5
.OMEGA./square, compared with 10.sup.10.2 .OMEGA./square on the
uncoated areas of the original belt. Visual print quality
assessment showed the print quality was equivalent to the original
belt. The method described herein for reconditioning an
intermediate transfer member by use of an overcoat provides added
life to used and/or damaged ITBs.
[0071] It will be appreciated that variants of the above-disclosed
and other features and functions or alternatives thereof, may be
combined into other different systems or applications. Various
presently unforeseen or unanticipated alternatives, modifications,
variations, or improvements therein may be subsequently made by
those skilled in the art, which are also encompassed by the
following claims.
* * * * *